Why do people scapegoat? Various reasons.
#1: People like feeling as though they have the answers. Even when they don't. Why do you think there are so many political and religious fanatics? Absolute certainty brings with it a self-righteous illusion of control. When the world doesn't work the way it should, it's the fault of X, Y, or Z--no matter how absurd, so long as it doesn't contradict whatever a person's starting beliefs are,
it's still more tenable to them than questioning themselves.
#2: Because pernicious bastards like to manipulate fear and anger. Common anywhere there's money to be made, or power to be gained. All you have to do is divide people into camps and convince the ones in your ideological camp to attack and hate those of any other camp--ideologically radicalize them. Anything will do, really. Fucking Nintendo and Sega did it to each other with attack ads (Nintendon't anyone?) that created two fan groups which each obsessed over the superiority of their system and the inferiority of every other system. It still lives on in a certain sense with the PC Master Race crowd, or the Sony Fantards or Microtards.
Thankfully, with game systems, it's just funny (and sad) to watch people zealously defend their own piece of overly expensive plastic. The same principle applies to politics though, schisming people into groups based on their values and getting them to attack anyone that is different. Blaming everything that's gone wrong on opponents. It's never done with evil intentions (on the surface anyway), it's almost always done with battle cries of "protect the X!" (Children, women, impoverished, whatever group garners the most sympathy) followed up with an absolute rejection of considering anything any other group may have to say. Typically by appealing to an absolute authority (ex: God, Allah, The Patriarchy, "The Natural Way of Things", et cetera) or by appealing to an absolute value (ex: Compassion, Love, Generocity, et cetera). It's almost always done by people who have something to gain by the status quo changing, or who at the very least benefit from saying that it should change.
#3: Because humans are a tribal animal. We identify to a series of values, and to a certain extent, anyone who doesn't conform to those values is a various degree of "other." The greater the strength of the belief, the greater the feeling of otherness gets. The greater the strength of the belief, the easier it is for others to manipulate one way or another, because it makes someone less likely to ever
question the source of that belief. It's easier to group people under other labels and judge everyone associated to that label rather than question ourselves.
At the end of the day, it's rather simple.
- Scapegoating is a tool used by people who need to feel as though there is an answer to all of their problems and uncertainties.
- It's generally perpetuated at the top by people who will manipulate with fear and anger.
- It's easiest to manipulate people who have a great and unwavering and unquestioned belief in something, as opposed to people who are willing to put aside their own feelings and beliefs to question themselves.
It goes back to the basic characteristics of good people and bad people. (Even if "good" and "bad" are subjective, and it's laughable to categorize most people as purely good or purely bad, here's a general sense of what to aim for. This also helps with writing characters in fiction, so if you still role play, take a note of it.)
Good people have a set of positive values or beliefs by which they live, and they hold
themselves accountable to those beliefs and values. Whenever something goes wrong in their life or in the world, they don't blame others--they simply set about to fixing it, and if they were in any way related to it occurring, fixing themselves.
Bad people have a set of positive values or beliefs by which they expect
everyone else to conform to in order to achieve their utopian ideals. Whenever something goes wrong in their life or in the world, they blame other people, other societies, other groups, other concepts, et cetera. This is in no way bound to any one group--the battle cry varies. "Build the wall to keep the Mexicans out" one group says, while another says "teach all men not to rape." Anything to force society to a utopian ideal that is most probably impossible so long as individuality exists, but by which they can hold everyone else accountable for failing to achieve--and never themselves.
Good people don't use scapegoats, because they have no need for them.
Bad people use scapegoats, because they have no other way of justifying their position than to invent conspiracies against themselves and/or their values and/or their beliefs.